And the icing on the cake came when she learned she had been specially chosen by Simon Cowell to take his top-rated TV show across the Atlantic.

Senior US executives from NBC are due to fly to Manchester this weekend to see her in action at the live auditions.

A source said: “Simon is on the brink of signing a deal to take The X Factor to America and, if he gets his way, Cheryl will be its star.

“He thinks she has amazing presence and her down-to-earth Northern charm will appeal to the American public. She is also an incredibly beautiful girl.

“She won’t get paid anything like the million pound salary she’s on here, because obviously she is not as well known in the States.

“But if it is a success, like most of Simon’s shows are, it could catapult her into the big league.”

It is understood Simon, 49, will not be able to appear on the show as he is tied into a deal with rival network Fox for American Idol.

The music mogul, who has an estimated fortune of £120million, has already announced he plans to quit after the next series of X Factor.

And he has made it clear he wants Cheryl to step into his shoes and become the main face of the show, which regularly pulls in around 15 million viewers.

ITV1 bosses are desperately trying to persuade him to stay, but while he wants to continue with Britain’s Got Talent, he feels it is time to move on.

Simon was at Cheryl’s bash on Wednesday at London’s Vanilla nightclub. Other guests included Cheryl’s bandmates Kimberley Walsh and Nicola Roberts and X Factor judges Louis Walsh and Dannii Minogue.

Hubby Ashley had secretly invited Cheryl’s showbiz pals, plus friends and family from Newcastle – treating them to flights and putting them up in hotels.

He even arranged for Cheryl – looking stunning in a frilly white mini-dress – to be presented with a giant pink birthday cake in the shape of a star. A friend said: “Cheryl just thought they were going out for a quiet meal.

“But when they pulled up outside the nightclub, she knew he had planned something special and she welled up with emotion.”